Known foam producing devices as shown in U.S. Pat. No. 3,709,437 employ a deformable reservoir containing foamable liquid and air, a discharge orifice, foam producing means including a foam homogenizing overlay or filter, and a ball check valve disposed in the foam producing means. The means also has air passages in a well portion which defines a mixing chamber. When the reservoir is compressed, the liquid and air are mixed in the chamber. The mixture is passed through the overlay to produce foam which is then discharged through the orifice. The check valve prevents downward flow of the liquid after the compression force in the reservoir is released, thus reducing the time to produce foaming upon subsequent compression. While the reservoir is returning to its uncompressed state after the compression force is released, air flows from outside the device in reversed direction through the same air passages into the reservoir for use in subsequent foam producing operations.
However, when these known devices are used for several foam producing cycles in rapid succession, a build up of foam will occur at the orifice, producing clogging. The devices then have to be unclogged before more foam can be produced. Moreover, the quantity of foam produced during each cycle is substantially reduced as compared to the immediately preceding cycle whereby the number of cycles required to produce foam, when these cycles occur in rapid succession, must be substantially increased to produce the same amount of foam.
The present invention overcomes these disadvantages by eliminating clogging and ensuring discharge of the same quantity of foam per cycle regardless of the rapidity of cycle succession.